Electrochemical Reduction of CO 2 by SnO x Nanosheets Anchored on Multiwalled Carbon Nanotubes with Tunable Functional Groups

ChemSusChem ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1443-1450 ◽  
Author(s):  
Qi Zhang ◽  
Yanxing Zhang ◽  
Jianfeng Mao ◽  
Junyu Liu ◽  
Yue Zhou ◽  
...  
Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 634 ◽  
Author(s):  
Shazia Shukrullah ◽  
Muhammad Yasin Naz ◽  
Norani M. Mohamed ◽  
Khalid A. Ibrahim ◽  
Nasser M. AbdEl-Salam ◽  
...  

Carbon dioxide is one of the major greenhouse gases and a leading source of global warming. Several adsorbent materials are being tested for removal of carbon dioxide (CO2) from the atmosphere. The use of multiwalled carbon nanotubes (MWCNTs) as a CO2 adsorbent material is a relatively new research avenue. In this study, Fe2O3/Al2O3 composite catalyst was used to synthesize MWCNTs by cracking ethylene gas molecules in a fluidized bed chemical vapor deposition (CVD) chamber. These nanotubes were treated with H2SO4/HNO3 solution and functionalized with 3-aminopropyl-triethoxysilane (APTS). Chemical modification of nanotubes removed the endcaps and introduced some functional groups along the sidewalls at defected sites. The functionalization of nanotubes with amine introduced carboxylic groups on the tube surface. These functional groups significantly enhance the surface wettability, hydrophilicity and CO2 adsorption capacity of MWCNTs. The CO2 adsorption capacity of as-grown and amine-functionalized CNTs was computed by generating their breakthrough curves. BELSORP-mini equipment was used to generate CO2 breakthrough curves. The oxidation and functionalization of MWCNTs revealed significant improvement in their adsorption capacity. The highest CO2 adsorption of 129 cm3/g was achieved with amine-functionalized MWCNTs among all the tested samples.


2016 ◽  
Vol 34 (3) ◽  
pp. 481-486 ◽  
Author(s):  
Łukasz Majchrzycki ◽  
Mariusz Walkowiak ◽  
Agnieszka Martyła ◽  
Mikhail Y. Yablokov ◽  
Marek Nowicki ◽  
...  

AbstractNowadays reduced graphene oxide (rGO) is regarded as a highly interesting material which is appropriate for possible applications in electrochemistry, especially in lithium-ion batteries (LIBs). Several methods were proposed for the preparation of rGO-based electrodes, resulting in high-capacity LIBs anodes. However, the mechanism of lithium storage in rGO and related materials is still not well understood. In this work we focused on the proposed mechanism of favorable bonding sites induced by additional functionalities attached to the graphene planes. This mechanism might increase the capacity of electrodes. In order to verify this hypothesis the composite of non-reduced graphene oxide (GO) with multiwalled carbon nanotubes electrodes was fabricated. Electrochemical properties of GO composite anodes were studied in comparison with similarly prepared electrodes based on rGO. This allowed us to estimate the impact of functional groups on the reversible capacity changes. As a result, it was shown that oxygen containing functional groups of GO do not create, in noticeable way, additional active sites for the electrochemical reactions of lithium storage, contrary to what has been postulated previously.


RSC Advances ◽  
2015 ◽  
Vol 5 (56) ◽  
pp. 44840-44846 ◽  
Author(s):  
Neda Mohaghegh ◽  
Masoud Faraji ◽  
Fereydoon Gobal ◽  
Mohammad Reza Gholami

MWCNTs/Ag/TiO2NTs plates were synthesized via electrochemical reduction of functionalized multiwalled carbon nanotubes (MWCNTs) on Ag/TiO2NTs.


2015 ◽  
Vol 761 ◽  
pp. 369-373 ◽  
Author(s):  
M.Y. Norazlina ◽  
S. Azizah ◽  
Mohd Fairuz Dimin ◽  
Y. Faridah ◽  
Omar Rostam

Commercially available Multiwalled Carbon Nanotubes (MWCNTs) were refluxed with nitric acid in order to improve the density of the acidic surface functional groups. The formation of oxygen containing functional groups may lead to surface enhancement of MWCNTs for further modifications. The crude MWCNTs were refluxed in nitric acid at 100 °C for time ranging between 3 to 24 h. The influence of treatment time on crystalline structure was investigated using X-Ray Diffraction (XRD); the results confirmed that all treated MWCNTs are crystalline. The density of the surface functional groups on treated MWCNTs was examined by Fourier Transform Infrared (FTIR). The FTIR spectrums revealed a strong vibration band at 1739, 1219, 1369 cm-1that indicates covalently bound acidic surface functional groups existed on the treated MWCNTs. The amount of acidic groups increased with the reflux time up to 15 h treatment as measured by an acid-base Boehm titration. The vibrational spectroscopy of these functional groups also increased with the increasing reflux time.


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